In the process of shipping an item from one location to another, a protective packaging material is typically placed in the shipping case, or box, to fill any voids and/or to cushion the item during the shipping process. Plastic foam peanuts and plastic bubble pack are two types of conventionally used packaging materials. These plastic materials, however, although performing acceptably in many packaging applications, are not without disadvantages. For example, one drawback of plastic bubble film is that it usually includes a polyvinylidene chloride coating which prevents the plastic film from being safely incinerated thereby creating disposal difficulties for some industries. Additionally, both the plastic foam peanuts and the plastic bubble pack have a tendency to generate a charge of static electricity that attracts dust from the surrounding packaging site. Furthermore, these plastic materials sometimes themselves produce a significant amount of packaging "lint." Such dust and lint particles are generally undesirable and may even be destructive to sensitive merchandise such as electronics or medical equipment.
Perhaps the most serious drawback of plastic bubble wrap and/or plastic foam peanuts is their effect on our environment. Quite simply, these packaging materials are not biodegradable and thus they cannot avoid further multiplying our planet's already critical waste disposal problems. The non-biodegradability of these packaging materials has become increasingly important as more industries adopt progressive policies of environmental responsibility.
These and other disadvantages of conventional plastic packaging materials have made paper protective packaging material a very popular alternative. Paper is biodegradable, recyclable and composed of a renewable resource, thereby making it an environmentally responsible choice for conscientious industries. Additionally, the recipients of the products may safely incinerate paper. Furthermore, paper protective packaging material is particularly advantageous for use with particle-sensitive merchandise, as its clean dust-free surface is resistant to static cling.
While paper in a sheet form could possibly be used as a protective packaging material, it is usually preferable to convert sheet stock material into a relatively low density pad-like cushioning product. A cushioning conversion machine may accomplish this conversion, such as those disclosed in U.S. Pat. Nos. 4,968,291 and 5,123,889. The entire disclosures of these patents, which the assignee of the present application owns, are hereby incorporated herein by reference in their entireties.
In a typical cushioning conversion machine, the stock material constituting the starting material for the conversion process will usually be composed of one or more plies of a sheet material rolled onto a hollow, cylindrical tube. Consequently, the stock supply assembly of the cushioning conversion machine is adapted to accommodate this stock material. Alternatively, fan-folded stock material may be used as in the manner described in commonly assigned U.S. Pat. No. 5,387,173.
Cushioning conversion machines in use today have a forming device and a feeding device that coordinate to convert a continuous web of sheet stock material (either single-ply or multi-ply) into a three dimensional cushioning product, or pad. The forming device is used to fold, or roll, the lateral edges of the sheet stock material inward on itself to form a strip of cushioning having a width substantially less than the width of the stock material. The feeding device advances the stock material through the forming device and it may also function as a crumpling device and/or a connecting (or assembling) device. The cushioning conversion machine may also include a ply separating device for separating the plies of the web before passing through the former.
Cushioning conversion machines heretofore have employed various assemblies for severing the continuous strip of cushioning into discrete sections or pads. Some machines have employed a cutting assembly that automatically produces cushioning pads of a given and consistent length. Others have employed a cutting assembly that requires an operator to manually control the length of the pad being cut. The cutting assembly in either the manual or non-manual system adds to the overall cost, size and complexity of a conversion machine. Also, the individual pads are formed only when the machine is operating. It would be desirable to provide a method of separating the strip of cushioning into discrete sections without the need for a cutting assembly and/or at a time other than when the strip of cushioning is formed.